1. Field of the Invention
This invention relates to a color filter substrate and a touch screen display device, more particularly to a color filter substrate for a display device integrated with a touch screen, and the display device integrated with a touch screen.
2. Description of the Related Art
A touch screen display device is a combination of a touch panel and a display device.
FIGS. 1 and 2 show a conventional liquid crystal display device with a capacitive touch screen, in which FIG. 2 is a fragmentary view taken along line II-II in FIG. 1. The liquid crystal display device includes: a touch panel 11, a liquid crystal display panel 12, a flexible circuit board 13 electrically connected to a control circuit (not shown), and a touch screen display region 14. The touch panel 11 has a transparent substrate 111, a touch sensor 112 formed on a surface of the transparent substrate 111, and a protective layer 113 covering the touch sensor 112. The touch screen display region 14 corresponds in position to the touch sensor 112. The liquid crystal display panel 12 includes a TFT (thin film transistor) substrate 121, a color filter substrate 122, and a liquid crystal layer 123 disposed between the TFT substrate 121 and the color filter substrate 122. The flexible circuit board 13 is electrically connected to the touch sensor 112 and the control circuit. When the touch screen display region 14 is pressed, the capacitance of the touch sensor 112 will change, thereby generating a touch signal. The touch signal is then transmitted to the control circuit through the flexible circuit board 13.
In the conventional liquid crystal display device, the touch panel 11 is adhered to a surface of the color filter substrate 122 of the liquid crystal display panel using an adhesive (not shown). However, with miniaturization of 3C products, reducing the thickness and weight of the touch screen display device has become a subject of endeavor in the industry, in which a liquid crystal display device integrated with a touch panel has been the target of development in recent years.
FIG. 3 shows a conventional touch panel-integrated liquid crystal display device 2. The major difference between the conventional touch panel-integrated liquid crystal display device 2 shown in FIG. 3 and the liquid crystal display device 1 of FIG. 1 resides in that, in the touch panel-integrated liquid crystal display device 2, the transparent substrate 111 used in the liquid crystal display device 1 of FIG. 1 is omitted and the touch sensor 112 is directly formed on the surface of the color filter substrate 122 so that the color filter substrate 122 also serves as the transparent substrate of the touch panel 11, thereby resulting in a reduction in the thickness and weight of the touch panel-integrated liquid crystal display device 2.
However, alignment of the flexible circuit board 13 with the touch sensor 112 in the liquid crystal display device of FIG. 1 is conducted using an optical alignment device that is disposed on the transparent substrate 111 so as to align and electrically connect the flexible circuit board 13 and the touch sensor 112. Since, in the liquid crystal display device of FIG. 1, the flexible circuit board 13 is connected to the transparent substrate 111, light generated from the optical alignment device may penetrate through the transparent substrate 111 without being obstructed. However, in the conventional touch panel-integrated liquid crystal display device 2 shown in FIG. 3, the transparent substrate is dispensed with and the flexible circuit board 13 is directly connected to a periphery of the surface of the color filter substrate 122. Since the periphery of the surface of the color filter substrate 122 to which the flexible circuit board 13 is connected is formed with a black matrix 124 that is used to isolate color filters and that is non-transmissible for light, may not be used a conventional optical alignment device to achieve alignment between the flexible circuit board 13 and the touch sensor 112.
The current alignment method is usually conducted to align the flexible circuit board 13 with the touch sensor 112 by virtue of an alignment pattern or through adjusting the position of a light source (illuminating toward front side or rear side of the transparent substrate 111). Since the black matrix 124 is non-transmissible for light, the alignment pattern will not be formed at the black matrix. However, the aforesaid alignment method cannot meet the requirement for mass production of the touch panel-integrated liquid crystal display device. Accordingly, how to seek an effective and precise alignment method is the subject of endeavor in the development of a liquid crystal display device integrated with the touch panel.